What is the substrate correction value based on?

The substrate correction value is based on the average of six XRF (X-ray fluorescence) readings taken from locations scraped free of paint. This approach is essential because it provides a more accurate assessment of the underlying lead-bearing substrate without the potential interference or variability that might arise from paint layers. By obtaining readings from areas that have been prepared in this way, assessors can ensure that they are measuring the lead content of the substrate itself, rather than reflecting lead that may be present within the paint layers.

This method helps in determining the correct risk associated with lead in the environment, as the presence of paint can mask or exaggerate the actual substrate lead levels. Therefore, using readings from scraped surfaces gives a clearer picture of the potential lead hazard present, informing remediation measures and safety assessments effectively.